The present invention relates to a thrust reverser actuator and, more particularly to a gearless electric thrust reverser actuator and a thrust reverser actuator system that incorporates the actuator.
When jet-powered aircraft land, the landing gear brakes and imposed aerodynamic drag loads (e.g., flaps, spoilers, etc.) of the aircraft may not be sufficient to slow the aircraft down in the required amount of runway distance. Thus, jet engines on most aircraft include thrust reversers to enhance the stopping power of the aircraft. When deployed, thrust reversers redirect the rearward thrust of the jet engine to a forward direction to decelerate the aircraft. Because the jet thrust is directed forward, the jet thrust also slows down the aircraft upon landing.
Various thrust reverser designs are commonly known, and the particular design utilized depends, at least in part, on the engine manufacturer, the engine configuration, and the propulsion technology being used. Thrust reverser designs used most prominently with turbofan jet engines fall into three general categories: (1) cascade-type thrust reversers; (2) target-type thrust reversers; and (3) pivot door thrust reversers. Each of these designs employs a different type of moveable thrust reverser component to change the direction of the jet thrust.
Cascade-type thrust reversers are normally used on high-bypass ratio jet engines. This type of thrust reverser is located on the circumference of the engine""s midsection and, when deployed, exposes and redirects air flow through a plurality of cascade vanes. The moveable thrust reverser components in the cascade design includes several translating sleeves or cowls (xe2x80x9ctranscowlsxe2x80x9d) that are deployed to expose the cascade vanes.
Target-type reversers, also referred to as clamshell reversers, are typically used with low-bypass ratio jet engines. Target-type thrust reversers use two doors as the moveable thrust reverser components to block the entire jet thrust coming from the rear of the engine. These doors are mounted on the aft portion of the engine and may form the rear part of the engine nacelle.
Pivot door thrust reversers may utilize four doors on the engine nacelle as the moveable thrust reverser components. In the deployed position, these doors extend outwardly from the nacelle to redirect the jet thrust.
The primary use of thrust reversers, as noted above, is to enhance the stopping power of the aircraft, thereby shortening the stopping distance during landing. Hence, thrust reversers are primarily deployed during the landing process to slow the aircraft. Thereafter, when the thrust reversers are no longer needed, they are returned to their original, or stowed, position.
The movement of the moveable thrust reverser components in each of the above-described designs has, in the past, been accomplished via hydraulic or pneumatic actuation systems. Hydraulic systems may include hydraulic controllers and lines coupled to the aircraft""s hydraulic system, hydraulic actuators connected to the moveable components, and electrically or hydraulically controlled locking mechanisms. Pneumatic systems include one or more controllers coupled to one or more pneumatic motors that are coupled to the thrust reverser moveable components via actuators.
More recently, however, thrust reverser actuation is being controlled by electric (or electromechanical) systems. These systems include one or more electronic controller units that control the operation of one or more electric motors. The electric motors are coupled to one or more thrust reverser actuators via reduction gears, which allow the motors to operate more efficiently at high rotational speeds. In some instances, the motors may be coupled to the actuators, without intervening reduction gears, via compound leadscrews.
The size and weight of current electric thrust reverser actuation systems, while suitable for large commercial jet aircraft applications, may not scale-down well for smaller jet aircraft applications, such as business jet aircraft. For example, the reduction gears between the electric motors and actuators may have an increased system size and weight, as compared to conventional small jet systems. This is partly because the actuation and sensing components associated with the system are individual, non-integral devices which are of a certain weight and space envelope. Thus, a smaller electric actuation system may be heavier and larger than a conventional non-electric actuation system. Thus, such a conventional electric actuation system may be impractical or inefficient because of its size and weight.
Hence, there is a need for an electric thrust reverser actuation system scaleable to small aircraft applications that includes electric actuators that are lightweight and compact, and that may include the actuation and sensing components in a single actuation package. The present invention addresses one or more of these needs.
The present invention provides an electric thrust reverser actuation system that includes electric actuators that are lightweight, and/or compact, and/or include the actuation and sensing components in a single actuation package. The actuators may, therefore, be utilized in relatively small jet aircraft applications.
In one embodiment of the present invention, and by way of example only, a system for controlling the movement of a jet engine thrust reverser includes a controller and at least two moveable actuators. The controller is coupled to receive command signals and is operable, in response thereto, to selectively supply actuator control signals. Each of the moveable actuators is operable to move the thrust reverser between a stowed position and a deployed position, and each has an electric motor, a rotationally mounted jack screw, and a roller nut. The electric motor has an output shaft, and is coupled to receive the actuator control signals from the controller and, in response thereto, to rotate the output shaft in one of a stow direction and a deploy direction. The jack screw has a first end directly coupled to the electric motor output shaft to thereby rotate in the stow direction and deploy direction. The roller nut is mounted on the jack screw and is coupled to one of the thrust reversers. Rotation of the jack screw in the stow direction causes translation of the roller nut and its associated thrust reverser toward the stowed position and rotation of the jack screw in the deploy direction causes translation of the ballnut and its associated thrust reverser toward the deployed position.
In another aspect of the present invention, an actuator including an electric motor, a rotationally mounted jack screw, and a roller nut. The electric motor has an output shaft operable to rotate in one of a first direction and a second direction. The jack screw has a first end directly coupled to the electric motor output shaft to thereby rotate in the first direction and second direction. The roller nut is mounted on the jack screw. Rotation of the jack screw in the first direction causes translation of the ball toward the first end and rotation of the jack screw in the second direction causes translation of the ballnut toward the second position.
In still another aspect of the present invention, an actuator with one or more integral locks is provided. Each of the locks is adapted to be pivotally mounted on the actuator and operable to selectively move between a locked position and an unlocked position and includes a first protrusion, a second protrusion, a third protrusion, a biasing element, and a solenoid. The first protrusion is adapted to engage a thrust reverser to thereby rotate the lock from the unlocked position to the locked position when the actuator moves from a first position to a second position. The second protrusion is adapted to engage the thrust reverser when the actuator moves from the second position to the first position. The third protrusion is adapted to cooperate with a position sensor to provide an indication of the position of the lock. The biasing element is mounted proximate to, and in abutting contact with, the second protrusion to thereby bias the lock toward the unlocked position. The solenoid has a moveable slug and is operable, in response to a lock control signal, to selectively move the slug so as to engage and disengage the lock.
Other independent features and advantages of the preferred actuator and actuation system will become apparent from the following detailed description, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention.